The ban is needed to encourage population growth, attorneys argued in a brief opposing a motion filed by a couple who have challenged the state’s ban on gay marriage.

April DeBoer and Jayne Rowse say the ban, which also bars same-sex joint adoptions, violates their 14th Amendment guarantee to due process.

Attorneys in Michigan Attorney General Bill Scheutte’s office argued that states that have defined marriage as being between “one man, one woman” have done so due to “the unique procreative capacity of such relationships benefits rather than harms society.”

The state’s attorneys argued that the couple should seek to overturn the ban through a ballot initiative rather than through the courts.